				DATA DESCRIPTION


Fugro-LCT, INC.
Job #7503

Seismic Australia

Otway/Sorell Basin
Offshore Australia

=================================================
PROPRIETARY DATA
NOT TO BE TRADED OR SOLD WITHOUT PERMISSION
Proprietary data belonging to:   FUGRO-LCT, INC.
=================================================

Marine gravity and magnetic survey

Date of CD creation: March 4, 2002

Description of files on the CD:

This CD contains three files as follows.

File1 - 7503_Linedata.asc = Line Data (ASCII code)
                           (logical record length = 216)

File2 - 7503_grids.asc = Grid Data (ASCII code)
                            (logical record length = 136)

File3 - CD_7503.fmt = File Description 
                               (Description of all files contained on TAR tape)
                               (logical record length = 80)

File4 - 7503_Fnl-Rpt.pdf = Final Data Processing report in Acrobat PDF format.

===============================================================

Projection parameters for X and Y coordinates are:

Projection           =         Universal Transverse Mercator 
Spheroid             =         Australian National
Central Meridian     =         141 E longitude
Base Latitude        =         0.0 N latitude
False Northing       =         10000000.0 meters
False Easting        =         500000.0 meters
Scale Factor         =         0.9996
 (along the central meridian)

===============================================================

7503_Linedata.asc - Line data (file number 1):

All data values for each observation are contained within a single record.
The record field structure for the line data is as follows:

                                                          COLUMNS    NO DATA
                                                                      VALUE
Field 1  = LCT Line number                                  4-8
Field 2  = Line Name                                       10-21
Field 3  = Julian date                                     23-25
Field 4  = Year                                            27-30
Field 5  = Hour                                            32-33
Field 6  = Minute                                          34-35
Field 7  = Second                                          36-37
Field 8  = Shotpoint                                       39-48
Field 9  = Latitude (decimal degrees)                      49-60   9999.999999
Field 10 = Longitude (decimal degrees)                     61-72   9999.999999
Field 11 = X-coordinate (meters)                           73-82    99999999.9
Field 12 = Y-coordinate (meters)                           83-92    99999999.9
Field 13 = Water Depth (meters)                            93-100     999999.0
Field 14 = Adjusted Water Depth (meters)                  101-108     999999.0
Field 15 = Corrected Meter Gravity (mGals)                109-117    999999.00
Field 16 = Eotvos Correction (mGals)                      118-126    999999.00
Field 17 = Free-Air Gravity (mGals)                       127-135    999999.00
Field 18 = Filtered Free-Air Gravity (mGals)              136-144    999999.00
Field 19 = Adjusted Filtered Free-Air Gravity (mGals)     145-153    999999.00
Field 20 = Filtered 3-D Bouguer Gravity  (mGals)          154-162    999999.00
Field 21 = Adjusted Filtered 3-D Bouguer Gravity (mGals)  163-171    999999.00
Field 22 = Raw Magnetics (nT)                             172-180    999999.00
Field 23 = Magnetic Anomaly (Cable,IGRF Corr.) (nT)       181-189    999999.00
Field 24 = Base Station Magnetics (nT)                    190-198    999999.00
Field 25 = Filtered Corrected Magnetic Anomaly            199-207    999999.00
           (Diurnal, Cable, IGRF Corr.) (nT)
Field 26 = Adjusted Filtered Magnetic Anomaly             208-216    999999.00
           (Diurnal, Cable, IGRF Corr.) (nT)


* Field 19, 21 and 26 Some data were deleted based on poor intersection
                      misties.  These data were derived from unadjusted
                      data containing these deletions.

The output format used to write these fields to
ASCII records was:

(3x,i5,1x,a12,1x,i3,1x,i4,1x,3i2,1x,f10.2,2f12.6,2f10.1,2f8.1,12f9.2)

The record length is 216 bytes / record.  Records are
fixed length.


===============================================================

7503_grids.asc - Grid Data (file number 2):

The second file contains the gridded data
used to generate the water depth, Free-Air gravity,
3-D Bouguer gravity and magnetic anomaly contour maps.
The second file describes a rectangular grid with an x-origin equal
to 525000.0 meters and a y-origin equal to 5724000.0 meters.
The grid spacing is equal to 1500.0 meters.
Each record in the file describes a single
row-column grid intersection value for water depth,
adjusted Free-Air gravity, adjusted 3-D Bouguer gravity and
adjusted magnetic anomaly. 
Null data values are represented by values equal to 1.0e20. 
The data fields are placed in each record as follows:

Field 1  = X-coordinate ( meters )
Field 2  = Y-coordinate ( meters )
Field 3  = Latitude ( decimal degrees )
Field 4  = Longitude ( decimal degrees )
Field 5  = Water depth ( meters )
Field 6  = Adjusted Free-Air gravity ( milligals )
Field 7  = Adjusted 3-D Bouguer gravity ( milligals )
Field 8  = Magnetic Anomaly (Diurnal Corrected)( nanoteslas )


The output format used to write these fields to was:

(4e18.10,4e16.8)

The record length is 136 bytes / record.  Records are
fixed length.


